The element selenium (Se) occurs in four common oxidation states. Two of these oxidation states, selenite, which is Se (IV), and selenate which is Se (VI), are believed to be acceptable for use in a nutritional product from a biochemical and medical perspective. Elemental selenium, Se (O), is not bioavailable as a source of selenium. Selenite is readily reduced to selenide, with is Se (II), and elemental selenium, be relatively mild reducing agents such as glucose, phosphorus acid, and iodide. In contrast, selenate is more difficult to reduce than selenite and thus, is less likely to form free selenium or selenides, including hydrogen selenide. This stability of selenate makes a selenate salt the preferred chemical form for the addition of selenium to a nutritional product.
However, selenite has been employed in nutritional products for the purpose of adding selenium to nutritional products. The incorporation of sodium selenite in a premixed combination of ingredients for use in a nutritional product has created several problems. These problems were manifested by the incomplete solubility of the premixed combination of ingredients and by a repulsive odor that emanated from the premixed combination of ingredients. The source of these problems stemmed from the interactions of sodium selenite with ferrous sulfate and cupric sulfate. Either or both of these salts, when ground together with sodium selenite, caused the reduction of sodium selenite to an insoluble reddish material, which is believed to be metallic selenium. A repugnant odor emitted from this mixture is believed to be hydrogen selenide which was formed as a byproduct of the same redox reactions. The problems may be significantly reduced by using special mixing techniques and/or the use of selenate in a premixed combination of ingredients for use in a nutritional product.